1. Field of the Invention
The invention relates to a metal pallet for containers, in particular large-volume containers. The metal pallet has a pallet top and pallet bottom for placing and securing a container on it. This metal pallet has stiffening formations, a molded-in support foot on the front side for receiving a draining device, and pallet feet in the corner areas connected to each other via a stiffening frame. Within the framework of the invention, containers are understood to be plastic containers for liquids and flowable products. These containers are surrounded by a jacket made of wire grating having regular horizontal and vertical lattice bars, as well as a filling and a draining opening. The plastic containers enclosed by the wire-grating jacket may have a holding capacity of 1000 liters or more.
2. Prior Art
Various types of metal pallets for containers are known. These metal pallets are designed for being handled by forklift trucks, shelf-serving devices or the like. They are provided with a bottom trough that receives the plastic container in a form-locked manner and also attaches the lattice jacket. The bottom of the pallet may have a draining gutter that extends with a slight gradient from the back wall of the container to the short draining pipe arranged on the front wall of the container. This draining pipe may be connected to a draining valve.
The bottom of the pallet may comprise stiffening formations and has an outer support edge that is drawn downwards. The bottom trough of the pallet is connected to the flat sub-frame making a hollow-chamber bottom with open chambers and an outer hollow support collar extending all around. The bottom trough is a deep-drawn component made of metal sheet comprising a center foot with a profile having a U-shaped cross section. The center foot is molded below the draining valve of the plastic container and is open in front and in the upward direction.
Furthermore, an angled edge strip may be made to form a sub-frame jointly with stiffening struts secured below the bottom trough (see DE 43 18 966). The known embodiment is structured from a multitude of individual components and therefore relatively complicated in terms of manufacturing and assembly techniques. For example, the feet of the pallet, as separate structural components, have to be screwed to a pallet frame designed in the form of a steel tube frame.
The feet of the pallet are designed as separate structural components and may also be attached by welding between the bottom of the pallet and the stiffening frame (see EP 0 989 071).
The known metal pallets are frequently unsatisfactory due to their instability. The storage containers comprised of the metal pallet and the container are subjected to stress such as shock or impact when crashing down from a loading ramp or falling off a hoisting gear. They may also be subject to vibration stress during transport. Therefore, permanent strength and a long useful life are demanded, particularly for metal pallets as well. Such requirements are generally not satisfied if the metal pallets are structured from a multitude of individual components. The invention is intended to provide a remedy in this regard.
The invention provides a metal pallet for containers, especially for large-volume containers of the type described above characterized by a particularly simple and stable type of construction. This stability assists regarding stresses caused by crashing, impacts and vibrations, and consequently establishes high permanent strength and a long useful life.
The bottom and the feet of the pallet are designed in the form of a one-piece structural component. The bottom of the pallet comprising the stiffening formations, the molded-in support foot and the molded-on pallet feet are produced from a pre-cut metal plate. This metal plate may be a steel sheet plate in the course of a drawing/reshaping process, such as a deep-drawing process and a reshaping bending operation.
The invention is based on the finding that a metal pallet can be produced in a simple manner in the form of a one-piece structural component with molded-on pallet feet, in a manner such that increased permanent strength and a longer useful life are obtained. In particular, the crash and impact stresses that must be regularly absorbed are more easily handled due to a substantial damping effect resulting from the molded-on feet of the pallet. Vibration stress is flawlessly absorbed as well because the feet and the bottom of the pallet form one single structural component. Increased manipulation, transport and accident safety are consequently achieved.
The feet of the pallet are produced from the metal attachments by bending the latter off and over, and the feet extend under the bottom of the pallet in order to obtain an optimal damping effect. This can be successfully accomplished particularly if the edges of the feet are joined with the pallet bottom by welding, clamping, or are secured on the pallet bottom in some other way. An additional support foot can be molded-in in the back of the metal pallet, or molded on from a metal attachment in the course of a reshaping bending process.
The stability of the metal pallet is increased further in that a drainage gutter is molded into the metal pallet, extending from the support foot in the back to the support foot located on the front with a predetermined inclination. This also assures flawless drainage of rain water between the container and the metal pallet.
To further increase the stability, permanent strength, and useful life of the metal pallet as defined by the invention, a stiffening traverse member is arranged on the pallet bottom. The stiffening traverse member extends in an orthogonal manner in relation to the drainage gutter from the one broad side to the other broad side of the bottom of the pallet. It comprises support feet on its ends, or it is connected to the support feet of the metal pallet. The stiffening traverse member is designed in the form of a multi-gutter section in which the cross section comprises a meander-like profile or alternating U-profiles. The pallet bottom comprises U-shaped molded recesses that engage the U-profiles of the stiffening traverse member, joining the pallet bottom in a form- and force-locked or positive manner. Furthermore, the stiffening traverse member with the support feet may be connected with the pallet bottom in the area of the support feet by welding, clamping, or in some other manner. According to another embodiment, it is possible also to weld-in or clamp-in the stiffening traverse member between the support feet and the pallet bottom, or to secure it there in some other way.
As a result, the metal pallet as-defined by the invention is comprised of only three individual components; the metal pallet with the molded-on pallet feet, the stiffening traverse member and the stiffening frame. Such minimization of the individual components optimizes the permanent strength and the useful life of the metal pallet as defined by the invention.
The stiffening beads or formations, which form depressions in the metal pallet are rectangles, squares or circles. The rectangles, squares or circles are preferably distributed across the surface area of the metal pallet in an axially symmetrical or mirror-symmetrical arrangement and may comprise diagonal or radial beads. The stiffening traverse member is usefully centered between the associated flanks of the rectangle or square formations bulging outwards from the pallet bottom.
The bottom of the pallet may comprise a dish-like receptacle for receiving the container with adaptation to the bottom of the container. To the extent that the container is substantially comprised of a plastic container with a wire grating jacket surrounding the plastic container, the bottom of the pallet comprises a installation groove for connecting the wire grating jacket on the peripheral side. The connection can be produced in the course of the process in which the wire lattice jacket is welded, clipped or screwed on.
Between the feet of the metal pallet and the support feet, the pallet bottom with the stiffening frame comprises slide-in openings that may be engaged by forklift trucks or similar hoisting gear. According to a preferred embodiment of the invention, the stiffening frame is recessed between the feet of the pallet and the support feet to the pallet bottom in order to further increase the stability of the metal pallet in the course of manipulation with a fork-lift truck and hoisting gear for large scale construction.